Python - Not finding armature
Look at the objects children
Instead of looking for objects with that parent, loop over that objects children.  All objects in a blend are in bpy.data.objects which may or may not be linked to a collection in the context scene.  Recommend working from scene rather than data, when applicable.
If the armature object &quot;Armature&quot; is in the scene iterate over its children.
import bpy

scene = bpy.context.scene
ob = scene.objects.get(&quot;Armature&quot;)

if ob:
    for c in ob.children:
        print(c.name, c.type)

To iterate over all objects in scene
for o in context.scene.objects:
    if o.parent == ob:
        print(o.name, o.type)

Do not confuse an object ss being the parent of its data.
The default armature object named &quot;Armature&quot;

The object (yellow with my theme)
&gt;&gt;&gt; C.object
bpy.data.objects['Armature']

has the data part (green)
&gt;&gt;&gt; C.object.data
bpy.data.armatures['Armature']